Evolution without the fossil record

[choccy]

Jerry Smith stated in another thread:

Furthermore, the abundant independent lines of evidence which converge on the one answer of common descent, but do not rely on fossils are conclusive by themselves.

I think this might be an interesting topic to explore further. What if we for some reason didn't have a fossil record? Would the other lines of evidence really be that conclusive? The reason why things like the Cytochrome C sequences posted here earlier are so convincing to me is that they match the fossil record almost perfectly. How would Cytochrome C have been evidence for evolution if we didn't have a fossil record to match it with? The only thing I can think of off the top of my head that would be fairly convincing without the support of a fossil record are things like similar errors in the vitamin C genes of both chimps and human, and the fairly strong evidence for a chromosome transfusion in human from the hypothesised (without a fossil record) common ancestors with chimps. There are people here who know a lot more about evolution than me, so let me know what you think.

Choccy

 

[Morat]

  Sure. Cytochrome-C isn't the only marker. It's just a good one because Cytochrome-C is used by pretty much everything, and there's such a huge array of functional versions of it. It's rare that a specific version is necessary for the species in question, which means it's free to vary.

   It forms a pattern, a particularly nested pattern. This pattern is matched by morphology, by retroviral insertions (old bits of viruses that got wedged into the genome), genetic mistakes, specific biochemical or morphological approaches to certain tasks, etc.

  What you get is you find this pattern is repeated any way you choose to look at it. Certain species are always "more alike", when studied, than others. (Of course, if you only look superficially, there are times when you might not see this. Bats and birds are roughly the same shape, for instance. They're built completely different, but roughly the same shape).

   Each method of looking reinforces the distance between species. Genetic insertions alone would have triggered the thought of common descent. How else do you explain the same viral DNA in the same spot in all these closely related species? 

 

[Jerry Smith]

Darwin relied less on the fossil record than comparative anatomy. Shared anatomical structures are good evidence of common descent in much the same way that shared derived traits in humans (racial, ethnic, or even strong family traits) are good evidence of common descent. If you see two oriental people, you can have certainty that they derive from common stock somewhere down the line. Other similarities will show that their common stock shares ancestors with all of the other racial or ethnic groups as well, only less recently. The same patterns of divergence of form show that humans and the apes share common ancestors, and phylogeny can be traced through comparative anatomy to relate most all living organisms to one another by common ancestors at some point in the past.

Microevolution is also good evidence for macroevolution. If we don't throw out the age of the earth, or the antiquity of life on it with the fossil record, we have to conclude that microevolution must have produced radical changes of the type that we see in common descent, or else we must find an explanation for why it didn't - given that much time, and given frequent speciation events that isolate gene pools.

 

[Morat]

  People who claim macroevolution can't happen (while admitting to microevolution or even better speciation), without showing a clear cause, are arguing that the base of a cone doesn't become wider the longer the cone is.

   They have to show, basically, that something stops the cone at a certain length, since they already admit the cone's length can grow.

 Edited in a fond hope to make it more clear.

 

 

[npetreley]

Wow. Evolutionists agree that they don't need evidence that evolution occurred in order to conclude that it occurred. What a surprise.

 

[ashibaka]

I really hope that was a joke, Petreley. [coughstrawmancough]

 

[Jerry Smith]

Wow. Evolutionists agree that they don't need evidence that evolution occurred in order to conclude that it occurred. What a surprise.

What are you calling evidence?

These are predictions from the theory borne out in observation.. If you have some other weird definition of evidence, please share it - and explain why that idea of evidence is better than the scientific one....

 

[Morat]

  He may have been referring to my post. I added a bit to clarify it. (Specifically, I added "while accepting microevolution and speciation". Something I'd implied, but not stated).

  To the overly literal person, it might have been interpreted as shoving the burden of proof on the negative claiment in it's original form.

 

 

 

[Jerry Smith]

How he got from that to all of us agreeing (with you?) that we don't need evidence to conclude evolution happened is way beyond me... But Ok.

 

[Jerry Smith]

Back on topic: has anyone mentioned biogeography? You know, marsupials on Australia & all? I assume we are not throwing out plate techtonics with the fossil record....

 

[choccy]

Originally posted by Jerry Smith
Back on topic: has anyone mentioned biogeography? You know, marsupials on Australia & all? I assume we are not throwing out plate techtonics with the fossil record....

That's a very good point. Has there been any research on how well the genetic differences matches the time the continents drifted apart? That would be almost asa convincing as matching the data with the actual fossil record.

Choccy

 

[Jerry Smith]

I think I recall something like that being done, but I don't know for sure. Maybe someone who does remember will bring that up.

 

[Jerry Smith]

Two other (related) categories of evidence that do not depend on the fossil record:

Vestigial structures: I will avoid the controversial human vermiform appendix, and focus on the obvious: Wisdom teeth. (I don't think this requires further clarification).

Atavisms: Like tails on humans:

Both examples from http://talkorigins.org/faqs/comdesc/section2.html , along with some very good explanations of how this data supports common descent/macro-evolution.

Really the fact that the bits of fossil record we do have line up perfectly with evolutionary theory is basically just the icing on the cake.

edited to fix url

 

[ardipithecus]

The previous post by Jerry Smith had an incorrect URL, it was missing the l in html.  The correct link is:

http://talkorigins.org/faqs/comdesc/section2.html

 

 

[Jerry Smith]

thanks!

 

[ardipithecus]

One of my favorite observation of something which makes utterly no sense without evolution:  teeth in toothless whales that never break through the gums and reabsorbed.

 

 

[Jerry Smith]

The list of atavisms & vestigial structures is near endless, but one easily observed vestigial structure is the dog thumb (cats have one too, I think - right seebs?) The little claw that terminates the inward facing phalange on a dog's limb is as "useless as teats on a boarhog" (if you are from the south). Yet dogs are stuck with them, because they come from five-fingered vertebrate stock. They are also quite prone to injury. I've had close experience with that too, having to bandage and medicate an injured one on a dog that I had a few years ago.

 

[seebs]

Introducing my assistant, the lovely and patient Greystoke. Show them your paw.

As you can see, there's a little nub of a toe on the back of the front paws, but not apparently on the rear paws. In a small number of cats, there's an extra toe which can be somewhat opposed to the others; cats with this "feature" are generally regarded as difficult pets, as they may eventually learn to open some doors or cabinets, and will certainly tip garbage cans.

The extra toe on cats isn't as obvious as what you describe in dogs; I think it's less pronounced.

Personally, I think the sheer similarity of unneeded features in cats and dogs pretty much answers the question. That, and the way they have the same joints we do, even though they have totally different uses for them.

BTW, I just got bitten for science. Not hard; Stokes is, as I said, a *very* patient animal.

 

[Jerry Smith]

LOL, thank you seebs and Greystoke!

 

[seebs]

Stokes is the science cat; he was the one my mom used as an example for her article on pet cloning. Everyone who knows him thinks that, while cloning pets to try to get the same pet is dumb, cloning a cat this unusual is interesting. He is probably the smartest cat I've ever had. He uses martial arts on the other cats; he's declawed, so he has to throw them. So, the other cat jumps at him, and he grabs the other cat, rolls, and body-slams the other cat. Who then slinks away looking very confused.